Multipurpose duplicating master



Jan. 11, 1966 J. R HEFFNER 3,228,327

MULTIPURPOSE DUPLICATING MASTER Filed April 5, 1962 2 Sheets-Sheet 1 F lG U R E 2 INVENTOR F GU R E 3 JAMES A /C/ /AAQ HEFF/VE/x ATTORNEY Jan.11, 1966 J. R. HEFFNER 3,228,327

MULTIPURPOSE DUPLI CATING MASTER Filed April 5, 1962 2 Sheets-Sheet 2SILICON OXIDE 00 FIGURE 4 \OO 97151 silicon oxide (0) 0.! POLYVNYLDIALDEHYDE ALCOHOL STARCH 0 media adhesion probiem b excessive inkrecepiiviiy INVENTOR. c =excessive water sensiiiviiy James RichardHeffner BY 1 I ATTORNEY United States Patent 3,228,327 MULTIPURPGSEDUPLlCATlNG MASTER James Richard Heifner, Kalamazoo, Mich, assignor toKY? Sutherland Paper Company, Kalamazoo, Mich, a corporation of DelawareFiled Apr. 5, 1962, Ser. No. 185,384 12 Claims. (Cl. 1il1149.2)

The present invention relates to coating compositions, sheet material ofa particular type coated with the particular coating compositions,duplicating masters made from such sheet material, and padded formsembodying such masters. The invention more particularly relates tocertain coating compositions and sheet materials coated therewith, andto duplicating masters made therefrom which have desirable andadvantageous characteristics not hitherto possessed by known duplicatingmasters, or sheet materials from which they have been made.

It is known in the art to reproduce printed, typed, or written matterfrom one sheet to another by various processes, including reproductiveprocedures of the offset or lithographic printing type, such as commonlyemployed using paper masters to produce copies on ordinary paper orso-called second generation masters for use in further reproductions bythe same process, or by differential light transmission-absorptionprocedures involving the differential transmission of light of variouswavelengths through a master to be copied and onto or into a secondsheet containing materials reactive to said wavelengths to produceindicia thereon and thereby provide duplicates or negatives of the sheetbeing copied, such as the diazo, photographic, or like processes, orinvolving the employment of differential transmission or absorption oflight wavelengths in the infra-red or heat-producing range, rather thanthe ultraviolet, to produce images and duplicates by means of a sheetsensitized to infra-red rays and/ or heat, or involving utilization ofelectrostatic phenomena. Each of these processes of reproduction has metwith success, in view of the ever increasing requirement for copies andmore particularly exact duplicate copies according to business practicesof today. The several processes have attained wide acceptance not onlyin separate fields of utilization, but also in overlapping areas, and insome areas due to efficient marketing practices all three types ofreproduction are employed, although by no means uniformly. Thus, forexample, in the freight-transfer industry, where the use of masters ofthe type concerned in the present invention and forms containing thesame is a uniform business control practice, all three of theaforementioned types of reproductive processes are presently in use,some firms employing one method or" reproduction and other firmsemploying another. However, since the several duplicating proceduresinvolve considerably different mechanisms, equipment of different designand nature is required for the employment or application of thedifferent processes. This heterogeneous disposition of the variousequipment for reproduction throughout the industry has resulted inwidespread delay and confusion, since it is uneconomic for every officeto be equipped with all three types of reproducing apparatus, althoughat any time any office may be Called upon to reproduce copies frommasters which are adapted for use with but one type of reproducingapparatus. It is apparent that, aside from the uneconomic possibility ofequipping each office with all types of equipment, the answer is toprovide a multi-purpose master which is adapted for use in any of thevarious reproductive processes with its particular type of equipment.

To state the obvious solution to this problem, however, is only topresent an entirely new project with many additional problems. For usein offset printing or lithography,

ice

a master must be adapted to receive ink and repel water in certain areasand to receive Water and repel ink in other areas. It must thereforepossess a desirable balance of hydrophilic and oleophilic properties, aswell as a requisite degree of wet tensile strength. For use indifferential light transmission-absorption types of reproductiveprocesses, a master must possess transparency or permeability so as toallow penetration of the particular wavelength of light necessary toeffect the reproductive color-forming reaction in the sensitized sheetadapted to respond to the differential impact of such rays. Thecombination of requisite characteristics for the various types ofreproducing masters has not previously been available in any one masteror in any one sheet material from which such a master might be formed,especially since the surface of such sheet material or master formedtherefrom must, for such multi-purpose adaptability, also be receptiveto a retentative of the different types of printing, typing, or writingmedia variously required for reproduction accord ing to the severalprocesses. As is well known, all of the processes will not reproduce allof the printing, typing, writing, or like media available, or even themedia required for reproduction according to other of the severalprocesses of reproduction. The few types of multi-purpose masters whichhave hitherto been available and utilizable for duplication according tomore than one of the several types of processes have all been attendedby difiiculties, such as lack of suflicient transparency, so that amaster which was utilizable in oifset printing procedures, whereutilizable at all in other types of duplicating procedures was notsufficiently effective to allow reproduction at a commerciallyacceptable rate. Conversely, masters utilizable in diiferential lighttransmission-absorption types of processes have been notorious for theirinadequacies when an attempt was made to employ same in offset printingor lithography. For example, one problem inherent in the production of amaster utilizable in both offset and diiferential lighttransmission-absorption reproduction processes is that it must not onlybe sufiiciently transparent and/ or penetrable to allow transmissionthereinto and/or therethrough of light rays diiferentially in the onetype of process, but it must also have a suificiently retentive surfaceso that media printed, typed or written thereon adheres sufiiciently tothe surface thereof and is not readily washed off during the processe oflithographing or oifset reproduction. Thus media retentiveness is afactor which must be considered in addition to thehydrophilic-oleophilic balance and the characteristic of wet tensilestrength requisite for offset or lithographic masters. The provision ofall such characteristics in one sheet material and a master producedtherefrom, as well as the requisite degree of transparency necessary forthe differential light transmission-absorption processes, has obviouslypresented a serious problem which has not been solved up to the presenttime. Provision of such a sheet material having the necessarycharacteristics to allow its employment in a duplicating master for usein all of the aforementioned types of duplicating processes, mastersproduced therefrom, and forms embodying such masters, would obviously beof considerable economic significance. Likewise, provision ofduplicating masters utilizable in all of the various aforesaidreproducing procedures at rapid and economically feasible rates would beof considerable importance.

It is accordingly an object of the present invention to provide novelcoating compositions, sheet material coated therewith, duplicatingmasters produced from such sheet material and adapted for multi-purposeuse, and forms embodying such masters.

An additional object of the invention is the provision of duplicatingmasters which are utilizable in and reproduceable by offset procedureand which are moreover utilizable as masters for reproduction by thevarious other processes hereinbefore mentioned at rapid and economicallyfeasible rates. a

A further object of the invention is the provision of a sheet materialor master which may be employed in the production of a second generationmaster by the offset process, which second generation master may thenserve as master in any of the aforementioned reproductive processes ofeither the offset or the differential light transmission-absorptiontype.

Other objects of the invention will be apparent to one skilled in theart and still other objects of the invention will become apparenthereinafter.

In accord with the present invention, the foregoing and additionalobjects have been accomplished by the provision of certain novel coatingcompositions, sheet material coated therewith, duplicating mastersthereof, and forms including such masters. The starting sheet materialcoated according to the invention has particular requisitecharacteristics and the coating composition involved, which is appliedto at least one surface of the sheet material, is in itself a particularcombination of at least two and preferably three different reactants,each having definite prerequisites, in definite proportions.

The invention is further illustrated by the drawings, in which:

FIGURE 1 is an edge View of a duplicating master produced from arelatively transparent sheet of paper uniformly coated on at least onesurface thereof in accord with the present invention;

FIGURE 2 is a top plan view of the duplicating master shown in FIGURE 1;and

FIGURE 3 is a top plan view of a padded form embodying the duplicatingmaster shown in FIGURE 2, with overlying sheets partially turned backand cut away to reveal the duplicating master.

FIGURE 4 is a graph illustrating the composition ranges of the threebinary coating compositions of the invention (lines A, A and A") and theternary coating composition of the invention (line B), as well as theotimum composition ranges for the preferred ternary coating compositionof the invention (line C).

The types of starting sheet material which may be employed in theproduction of the coated sheet and masters made therefrom according tothe present invention are those sheet materials permitting a minimumultraviolet light penetration of twenty-five (25) percent and preferablyin excess of forty (40) percent, as compared with air, using anultraviolet beam having a peak of about 3650 Angstrom units, astransmitted through Corning filter No. 5860 (or Photovolt No. 5162) asdetermined with a photoelectric transmission densometer (Photovolt No.5012). Included in such types of sheet material may be mentioned anybase sheet stock of paper or other material such as regeneratedcellulose, cellulose acetate, or other papers and sheet materials ofsuch requiste degree of ultraviolet transmission, including for examplethe type of paper known as greaseproof paper, which is made from highlyhydrated machine calendered pulp according to procedure well known inthe art, or glassine papers of various types (which are supercalenderedgreaseproof papers), or other papers transparentized in the usual maner,according to procedure customarily employed in the paper industry,before application of the coating composition, in each case with orwithout surface pretreatment which does not materially alter thetransparency of the sheet material for purposes of making the same morereceptive to the coating composition of the present invention. Anespecially preferred starting sheet material is parchmentized paper,especially 25 to 50 pound per 3000 square feet parchmentized paper, suchas commonly produced in the paper industry using concentrated sulphuricacid and as more recently known also produceable using concentratedortho-phosphoric acid. The additional characteristics requisite in suchstarting sheet material to be coated are that it should have, inaddition to the minimum degree of ultraviolet transmission, a minimumwet tensile strength of two (2) pounds per inch (machine direction) asdetermined by TAPPI test method T 456 m49. Since the coating compositionused in the invention is transparent, it is only necessary to providesuch starting sheet material as has the aforementioned characteristics,and then to coat such sheet material uniformly, thereby to impart to atleast one surface thereof the characteristics of hydrophilic-oleophilicbalance and ink retentiveness afforded by the present invention.

While some of these starting papers or sheet materials, such asparchment, are not only transparent but can also be used as an offsetmaster, without modification, when so employed they still leave much tobe desired in view of their characteristic pick up of ink in thenon-printed background areas and corresponding lack of contrast in andlegibility of the finished reproduced product. Also, whereas variouspapers and other sheet materials have already been coated with numerouscoating materials, including polyvinyl alcohol and the like, the coatingmaterial of the present invention involves a particular combination ofspecific ingredients in particular proportions, which appear to becritical for attainment of the desired results.

The transparent or substantially transparent coating compositions of theinvention may be formed from any one or more of the followingcombinations:

I. Binary (a) polyvinyl alcohol having certain prerequisites anddialdehyde starch, also having certain prerequisites.

(b) polyvinyl alcohol having certain prerequisites and a silicon oxide,also having certain prerequisites.

(c) a silicon oxide having certain prerequisites and dialdehyde starch,also having certain prerequisites.

Preferably, however, the composition is formed from the followingcombination:

II. Ternary (d) polyvinyl alcohol, and dialdehyde starch and a siliconoxide, all having particular prerequisites.

Mixtures of the binary systems may also be employed, the resultingcomposition of course being a ternary composition.

The prerequisites of the respective ingredients are as follows:

Polyvinyl alcohoL-The polyvinyl alcohol employed has at leastninety-five percent and preferably a higher percentage of its existinghydroxyl groups present as free unesterified hydroxyl groups, preferablyeven as high as 99% or higher, that is, as close to 100% as possible.Such materials are commercially available and in most cases, due totheir method of production, will contain acetate groups to the extentthat hydroxyl groups therein are still esterified. Such materials are,for example, presently available under the Evanol (Du Pont) trademark.Polyvinyl alcohols of the stated prerequisite hydroxyl content having aviscosity (4% solution in Water at 20 C. determined by Hoeppler fallingball method) in centipoises of 4-6, 23-28, 28-32, 45-55 and 5565, haveall been found operative.

Dialdehyde starch.-The dialdehyde starch employed is disclosed in US.Patents 2,648,629 and 2,713,553, and is starch containing polymeric2,3-dialdehyde derived therefrom by oxidation to the extent of at leastabout fifty percent aldehyde content, usually at least about 75% andpreferably above 90% aldehyde content. Such materials are alsocommercially available in the form of dialdehyde starch having2,3-dialdehyde content within the ranges indicated, especially under thetrademark Sumstar. Reference is made to the publication entitled SumstarDialdehyde Starch, Technical Bulletin No. 6-129, published by MilesChemical Company, Elkhart, Indiana (Copyright 1959).

Silicon 0xide.-The prerequisites of the silicon oxide is that it be asolid hydrophilic water-insoluble silicon oxide having an averageparticle size of two microns or less, usually less than .05 micron, andpreferably between about .015 and .02 micron, as measured on its largestparticle diameter, and a refractive index (12 not greater than 1.6. Anysilicon oxide of these properties is operative. The silicon oxide ispreferably isotropic, by which is meant that the material is opticallyhomogeneous, having only one index of refraction. A characteristic andpreferred silicon oxide is the colloidal silica (silicon dioxide)prepared in hot gaseous environment by vaporphase hydrolysis having anaverage particle size of 0.015- 0.02 micron, an external surface area ofabout 175-225 square meters per gram, and about 99.9% silicon dioxidecontent on a moisture-free basis, such as that sold under the trademarkCAB-O-SIL by Cabot Corporation, Boston 10, Mass.

The operative ranges of ingredients for the coating combinations orsystems identified above are as follows, the total number of parts ofthe stated ingredients being 100:

Table I PVA Silicon oxide G. 40 or less.

In preparing the preformed coating compositions of the invention, thefollowing procedure is employed.

When polyvinyl alcohol is used as one ingredient of the composition, thepolyvinyl alcohol is in any event placed in solution in a volatile,non-reactive solvent, usually an aqueous, preferably water, solution.When dialdehyde starch is a second ingredient of the composition, thisis also placed in the same type solvent. When both polyvinyl alcohol anddialdehyde starch are employed as ingredients of the composition, theirrespective solutions are combined, preferably by adding the dialdehydestarch solution to the polyvinyl alcohol solution. In the event siliconoxide is to be a second or third ingredient of the composition, this maybe combined with either of the solutions or with the combined polyvinylalcohol-dialdehyde starch solution. The silicon oxide when to be presentin the combination may be added in either the dry state or as an aqueousslurry, preferably as a slurry in water. Combination of the ingredientsinto solutions or suspensions containing preselected quantities of thesame produces a final coating composition having the predetermined ratioand amounts of the components. Although in some cases heating of thesolvent and polyvinyl alcohol to a temperature as high as 195-205degrees Fahrenheit is advantageous in effecting solution of thepolyvinyl alcohol, and although the solvent and contained dialdehydestarch is frequently heated to a temperature as high as 160 degreesFahrenheit to effect its solution, care should be exercised that thedialdehyde starch is not heated substantially above 200 degreesFahrenheit, either alone or in combination, for prolonged periods.

The ratios of polyvinyl alcohol and dialdehyde starch which have beenfound suitable for preparation of binary coating compositions accordingto the invention are as indicated in the foregoing Table I, with a ratioof about ten parts of polyvinyl alcohol to one part of dialdehyde starchbeing optimum, especially when starch containing above about 90% of the2,3-dialdehyde and polyvinyl alcohol containing at least about 99%unesterified free hydroxyl groups are employed. At the higher ratios ofpolyvinyl alcohol to dialdehyde starch, polyvinyl alcohol having a lowerpercentage but still in excess of free unesterified hydroxyl groups maybe employed, while at the lower ratios of polyvinyl alcohol todialdehyde starch, starch having a lower percentage but still in excessof 50% dialdehyde content may be employed. Likewise, while adequatehydrophilic-oleophilic balance and satisfactory freedom from tendency towash is obtained using polyvinyl alcohol having a high degree, nearly offree unesterified hydroxyl groups and dialdehyde starch having a lesserpercentage but always at least 50% 2,3-dialdehyde content, or employingpolyvinyl alcohol having a lesser percentage but always 95% or greaterfree unesterified hydroxyl groups and dialdehyde starch having a high2,3- dialdehyde content of about 90% or above, the optimumhydrophilic-oleophilic balance appears to be effected at between athreeztwo and a fiftyzone ratio, preferably at about a ten to one ratio,of polyvinyl alcohol having about 99% free unesterified hydroxyl groupsand dialdehyde starch having at least about 90% 2,3-dialdehyde content.

By way of illustration, using the PVA and DAS and the binary compositionas representative, polyvinyl alcohol and dialdehyde starch may be mixedtogether in the proper ratios and applied to the sheet material to becoated in the form of a solution or dispersion of the resulting product.At least a part and usually all of the product is in solution. Thepolyvinyl alcohol is usually placed in solution, the starch having therequisite dialdehyde content is placed in solution, and the lattersolution added to the former. Other orders of admixing the reactants maybe employed. The solvent employed for the components may be anynonreactive volatile solvent which may be evaporated from the surface ofthe sheet material after coating to provide a uniform layer of thedialdehyde starch-polyvinyl alcohol composition on the surface of thesheet material treated. A preferred solvent for obtaining the desiredsolution of the polyvinyl alcohol and the dialdehyde starch is water,with or without minor amounts of alcohols, dioxane, plasticizers or thelike, although any other nonreactive volatile solvent which dissolvesthe components and will volatilize upon standing in dry air or upon theapplication of heat may be employed. When the dialdehyde starch does notgo readily into solution, a solubilizing agent such as sodium acetate,sodium bisulfite, disodium phosphate, borax, or the like, in amount ofabout one to five parts per hundred parts of solvent, may be employed.Solution of the dialdehyde-starch is ordinarily readily obtained byslight heating as to about -160 degrees Fahrenheit and agitation of themixture of dialdehyde starch and solvent. Rapid solution of thepolyvinyl alcohol may be readily effected according to conventionalprocedure. According to a preferred procedure, separate solutions ofpolyvinyl alcohol and dialdehyde-starch are prepared and admixed and themixture thereafter agitated, although slight heating as to about 140-160degrees Fahrenheit may also be employed to effect a more rapid solution,which is ordinarily complete in thirty to sixty minutes or so. Settingof the composition on the sheet material is effected during thesubsequent drying or heating to to volatilize the solvent.

After the two solutions are admixed, or When the ingredients arecombined together in any other manner to provide a solution of thecomponents, it is only necessary to provide sufficient of a uniformcoating or" the composition on the surface of the starting sheetmaterial to attain at least a five (5) pound per inch (machinedirection) wet tensile strength (TAPPl T 456 m-4-9) of the coated sheetmaterial when the starting sheet material has less than this requisitestrength to begin, and this may be accomplished in conventionalsurface-coating manner by the employment of a coating head such as aroll coater, a trailing blade or an air brush, or on a size press, allas commonly employed for surface coating. When coating compositions ofthe invention containing combinations of ingredients other than PVA andDAS, or additional ingredients, are prepared and employed, the procedureis substantially the same, in accord with the more general proceduraldirections already given.

The total solids in the coating compositions of the invention, prior tobeing coated upon the base sheet material, may vary over a wide range.For example, concentrations of total solids from one percent to aboutsixty percent are operative, with from about three percent to aboutfifteen percent being preferred for ordinary highspeed coating methods.The amount of total solids in the composition may be advantageouslyincreased in some cases, as when thinner starting sheet materials areemployed. In other cases, more than one coating may be applied, althoughthis is not preferred for reasons of economy. The concentration of totalsolids in the coating composition is only limited by the highestconcentration which may be conveniently handled using available coatingequipment at economical coating speeds. In some applications it isadvantageous to employ a plurality of coatings, as in cases where a moreuniform coating is desired, in which cases double coating heads may beemployed, with or without drying in between. Although both sides of abase sheet material may be coated at the same time, as in a size press,it is sometimes advantageous to coat the sides individually, and thismay be conveniently accomplished for example by individual passes with atrailing blade coating head.

The total solids coated on the base sheet material in this manner shouldbe in the range of 0.1 to thirty pounds per ream (3,000 square feet) perside of base sheet material, whether coated on one or both sides, andthe preferred range is from 0.2 to five pounds total solids per ream(3,000 square feet) per side of base material, again whether coated onone or both sides. The concentrations of the coating compositionsemployed to obtain this desired result are never less in total solidscontent than the desired total solids content desired to be obtained onthe base sheet material by a single application and the exact solidsconcentration of the composition will depend upon various factors suchas the method of application, the rate of application, and whether oneor more coating applications are to be made on the surface of the basesheet material.

In the event it is desired to produce the coated sheet materials of theinvention otherwise than by employment of a preformed coatingcomposition, this may for example be accomplished by minor proceduralvariation, as

by coating the sheet material with the polyvinyl alcohol in solution,allowing the coating to partially dry, gel, or set, and then overcoatingwith dialdehyde starch solution, if desired containing the siliconoxide. This is productive of a coating having the requisitecharacteristcs and relative ratios of ingredients, providing only thatthe amounts of solids in each of the several solutions be preselected inaccord with the ranges previously stated. Similarly, when polyvinylalcohol and silicon oxide are to be used in a binary system, or whendialdehyde starch and silicon oxide are to be used in a binary system,the same procedure may be employed, with the initial coating in eachcase being with the polyvinyl alcohol, when present in the composition,or with the dialdehyde starch solution, when present in the composition.

For final production of the coated sheet material, the sheet, alreadycoated as above described, is dried as in heated dry air, onsteam-heated rollers, with a gas flame, or combinations thereof,preferably at incremental tem peratures, during which drying the settingof the transparent coating composition on the sheet material iscompleted. The coated sheet may if desired be supercalendered to improveits surface and provide better ink lay, to decrease caliper and therebyalso improve transparency, and to generally improve its appearance,although supercalendering has not been found necessary toprovide asuitable coated sheet material product for use in accord with thepresent invention. The coated sheet material may finally be stored orcut into sheets of suitable dimensions. Inasmuch as the coatingcompositions when set on the base sheet material are transparent, theminimum total solids content of 0.1 to thirty, preferably 0.2 to five,pounds of total solids per 3000 square foot ream per side of sheetmaterial, the minimum wet tensile strength of five pounds per inch(machine direction) by TAPPI tests T456 m-49, and the same minimum ultraviolet transmission properties set forth above for the starting sheetmaterial (namely at least 25% and preferably at least 50% as comparedwith air), are all characteristics of the coated sheet material of theinvention.

In the preparation of masters, the coated sheet material is either firstprinted as desired and then cut or alternatively cut to desireddimensions and then printed, but preferably the former, all according toconventional procedure in the printing and business forms producingindustry. The text and/or vertically and/ or horizontally arranged linesand/or columns may be printed on the master in any desirable orconvenient manner, again as conventional in the art. The medium for suchprinting of the master, however, should be such as will reproduceaccording to :any of the several methods of reproduction, if it isdesired that such printed material shall reproduce along with addedmaterial. The printed form may in some cases be printed with media whichis nonreproductive in any of the various reproducing processesmentioned, although just the reverse is preferred. For certainapplications, it is acceptable that the master have no printing whateverthereon, as in those cases where only the printed, typed, or writtenmaterial subsequently added is desired to be reproduced. In practice,the masters may be directly extended, i.e., printed, typed, or writtenupon, with many of the usual printing, typing or writing media, selectedfor their ability to reproduce in the several processes of interest,whereafter reproductions can be run off from the master which asindicated is thus made directly by inscribing or imprinting reproducingindicia upon the face thereof, rather than indirectly by means of anadjacent carbon sheet, as in a pad. Alternatively, reproducing indiciamay be placed upon the master indirectly, as by means of carbon paper ora pigment-coated transfer sheet.

In the preparation of forms embodying the duplicating masters, sheetsare cut from usual paper stock of the type employed in composing suchforms, printed with the usual text material and/or vertically and/orhorizontally disposed lines and/or columns, and arranged together withthe duplicating master which may also be, and which preferably is,imprinted or inscribed with the identical text and arrangement of linesand columns as is provided on the other sheets of paper from which thecompleted form is to be composed. Sheets of carbon paper, preferably ahard carbon type, of the same dimensions are dis-posed between thevarious sheets of printed forms and between a sheet of printed form andthe master. A backing sheet of heavier weight may or may not beprovided. The sheets are usually so arranged that printing, typing orwriting on the uppermost sheet produces an impression on :all of theunderlying sheets so as to transfer an image of the added printed, typedor written material to all of the underlying non-carbon sheets and tothe master. The so-arranged sheets are glued at their upper edges, orsuch edges may be glue dipped so as to provide a pad of sheets securedtogether at its upper edge. A perforation line is ordinarily provided inspaced parallel relation to the glued edge, for rapid and convenientdisassembly of the pad into its individual sheet components. In someembodiments, while arranged together in pads, the sheets are not securedtogether, but may merely be placed underlying each other and held inplace, or for instance so arranged in a ring or other binder.

Referring now to the drawings for a more complete understanding of theinvention, FIGURE 1 is an edge view of a duplicating master 10 producedfrom a sheet of relatively transparent paper coated in accord with thepresent invention. FIGURE 1 shows paper sheet 12 and the coatingcomposition layer 11 on the upper surface thereof. The broken linesindicate a coating composition layer 13 which may be present on theunder surface of said paper sheet, and the presence of which coatinglayer 13 constitutes a preferred embodiment of the invention.

FIGURE 2 shows a plan view of a duplicating master 1:), the edge view ofwhich is shown in FIGURE 1. The coating layer 11 is shown facing theviewer. Variously arranged printed text and horizontally and verticallydisposed lines are provided on the surface of the sheet, as at 14. Theprinted text and horizontally and vertically arranged lines 14 eithermay or may not be in ink of a reproducing nature according to one ormore of the various processes of reproduction, but are preferablyreproducible by all processes.

FIGURE 3 shows a plan view of a padded form in accord with theinvention, embodying master 10. Padded form 20 includes the usualrelatively light-weight top paper sheet, as commonly employed in thebusiness forms industry, having text material and vertically andhorizontally arranged lines printed upon the surface thereof, as at 24.Carbon paper sheet of common hard carbon type is interposed betweenupper paper sheet 21 and master 10, having coating layer 11 upwardlydisposed. Printed text and vertically and horizontally arranged lines 14on coating layer 11 of master 10 are in registry with printed text andvertically and horizontally arranged lines 24 on top paper sheet 21. Thevarious sheets 21, 25, and 10 comprising padded form 20 are joined attheir top edges as by gluing so as to constitute them into an assembledpad 20 until tear strip 22, to which the sheets are all integrallyjoined along perforation line 23, is removed, thereby severing thepadded form 20 into its individual sheet components. To the extent ofthe registry of printed text and lines 14 and 24, respectively, providedon coated surface 11 of master 10 and on sheet 21, the filling in ofblanks or the addition of textual material on sheet 21 will provide amaster 10 which is an exact duplicate of top sheet 21, due to the carbonsheet 25 disposed thereinbetween.

Referring now to FIGURE 4, there is shown a composition diagram for thevarious coating compositions of the present invention. The linesdesignated A, A and A" define the ranges for the three binary coatingcompositions of the invention, while the area enclosed within the linedesignated B defines the composition ranges for the preferred ternarycoating composition of the invention. A single diagram is used forconvenience of illustration, it being understood that as shown for theternary system line B cannot be zero at any point. Line C encloses theoptimum ranges for the ternary system. As will be seen from FIGURE 4,the composition may contain only two components or three components. Theranges of the components as shown in FIGURE 4 are identical with thoseset forth in Table I hereof. The optimum ranges for the preferredternary coating composition of the invention, as seen from FIGURE 4, arefrom 0.1 to 55 parts of dialdehyde starch, from 15 to 97.5 parts ofpolyvinyl alcohol, and from 0.1 to 65 parts of silicon oxide, the totalnumber of parts being 100, so that the figures not only express partsper 100 but also weight percent. Within the optimum ranges for theternary composition (line C) all of the advantages set forth previouslyfor the present invention are uniformly obtained, as within this area asuperior balance of offset properties are procured without detriment tothe properties required for other reproduction processes. In the areabounded by the line designated B, the ranges are from 0.1 to 72 parts ofdialdehyde starch, from 0.1 to 97.6 parts of polyvinyl alcohol, and from0.1 to parts of silicon oxide, per parts of composition, and withinthese ranges the ternary composition is characterized by a balance ofdesirable properties which is superior to that exhibited by any of thevarious binary compositions of the invention. As will be seen fromFIGURE 4 in area a the adhesion of reproductive media to the sheetmaterial becomes a problem, whereas in area b excessive ink receptivityis encountered, and in area 0 excessive water sensitivity, which alsoresults in wash-off of the media such as ink from the master, isexperienced. In area a, the problem is due to lack of anchorage ratherthan water sensitivity.

The following examples are given by way of illustration only and are notto be construed as limiting.

Example 1.Binary PVA-l-DAS A solution was prepared by adding three partsof polyvinyl alcohol (Evanol 72-60; 55-65 c.p.s. viscosity, 99- 100%free hydroxyl groups) to 97 parts of water and agitating for five to tenminutes. Heat was applied until a temperature of 195 to 205 Fahrenheitwas attained and this temperature was maintained until solution wascomplete. In various runs, the time required for complete solution wasusually thirty to sixty minutes.

A dialdehyde starch solution was prepared using 100 parts of water inwhich one part of sodium acetate was dissolved. This solution was heatedto Fahrenheit, agitated constantly, and ten parts of 90% oxidizeddialdehyde starch (i.e., starch having a starch 2,3-dialdehyde contentof at least 90%) (Sumstar S or 190A) was added slowly so that uniformwetting occurred. Agitation was continued at 160 Fahrenheit for thirtyminutes.

After cooling the polyvinyl alcohol solution to room temperature,sufiicient of the 90% oxidized dialdehyde starch solution was addedthereto so as to give a ratio of ninety parts of PVA to ten parts ofDAS. After thoroughly mixing, the solution was applied to 28 lb./ reamparchment paper by means of a size press.

Drying and setting of the coating on the parchment was accomplishedusing a gas flame and regular steam-heated dryer drums with incrementalheating of the rolls from 190 F. to 240 F. The transparently-coatedstock was supercalendered to improve smoothness of surface for betterink lay, to decrease caliper and increase transparency, and to improveappearance.

Some of the stock was cut into 8 /2 x 11 inch grain long sheets, whichwere then imaged upon so as to provide an arrangement of lines of thenature shown in FIGURE 2 hereof. These sheets were now masters.

Duplication using these masters was elTected using three differentoffset duplicating machines including two different types, viz.,Davidson Model 241 and Addressograph- Multigraph Model 1250, in each ofthe three cases using the particular etching solution and fountainsolution provided for normal use with the machine in question. Resultsfrom all three offset duplicators was very satisfactory for 20-30copies, with excellent reproduction of second generation masters, whichin turn gave excellent reproduction when they were tested as masters.

Diazo reproduction using the masters of either first or secondgeneration was excellent at speeds of 21 to 24 ft./ min. on an Ozaliddiazo reproduction machine Model OM16.

Reproduction using the masters on a standard Thermofax machine Model 17]gave excellent copies.

Example 2.BinaryPVA+Silicon Oxide A PVA solution was prepared from thesame ingredients and in the same manner as given in Example 1. An amountof colloidal silica having an average particle size between 0.015 and0.02 micron, a surface area of about 225 square meters per gram, an 11of 1.55, and a 99.9% silicon dioxide content on a dry basis was added toequal the weight of the polyvinyl alcohol in the solution, therebygiving a 1:1 weight ratio (50 parts to 50 parts). Application, setting,and testing were accomplished in the same manner as given in Example 1.The reproduction test results using the master thus produced were equalto those indicated in Example 1.

Example 3.Binary-Silicon Oxide-l-DAS Dialdehyde starch (90% oxidized)solution was produced as in Example 1 and diluted to a three percent byweight solution by addition of water. To this solution was added withstirring colloidal silica (having an average particle size between 0.015and 0.02 micron, a surface area of about 175225 square meters per gram,an n of 1.46, and a 99.9% silicon dioxide content on a dry basis) in anamount equal to that of the dialdehyde starch, so that a 1:1 weightratio of silica to dialdehyde starch existed (50 parts to 50 parts).Application, setting, and testing were accomplished in the same manneras given in Example 1. The reproduction test results using the masterthus produced were equal to those indicated in Example 1.

Example 4.TernaryPVA, DAS and Silicon Oxide Ten parts of PVA (99-100% offree hydroxyl groups) were added to 100 parts of water and the mixturewas agitated for ten minutes. Heat was applied until a temperature of195 to 205 F. was reached and this temperature was maintained untilsolution was complete, which usually required 3060 minutes.

A solution of dialdehyde starch (90% oxidized) was prepared as describedin Example 1.

After the polyvinyl alcohol solution had cooled, dialdehyde starchsolution was added thereto and the solutions thoroughly admixed. Thequantities were selected to provide two parts of dialdehyde starch toone part of polyvinyl alcohol in the solution. Thus, after addition, theproduct was a three percent PVA and six percent dialdehyde starchsolution. Colloidal silica (having an average particle size between0.015 and 0.02 micron, a surface area of about 175-225 square meters pergram, an 11 of 1.46, and a 99.9% silicon dioxide content on a dry basis)was added, in an amount equal to the weight of the polyvinyl alcoholpresent, so that 50 parts of dialdehyde starch were present for each 25parts of PVA and each 25 parts of silicon oxide.

The coating composition was applied by size press to a 28 poundparchment paper. Drying and setting of the coating was effected withsteam-heated dryer drums. The transparently-coated stock wassupercalendered to improve sheet appearance, to improve smoothness forbetter ink lay, and to decrease caliper for better ultra-violet lighttransmission. In this case, supering was done on a small handsupercalender. I

Both supered and non-supere sheets were converted to imaged masters asin Example 1 and tested on the three separate offset duplicationmachines using each machines own etching solution and fountain solution,just as in Example 1. All masters tested produced at least 20 excellentcopies, as well as excellent second generation masters, which in turnproduced excellent copies.

Diazo reproduction from the masters was excellent using speeds from 21to 24 ft./ min. on an Ozalid diazo machine Model OM-16.

f Thermofax reproduction on a Model 17] Thermofax machine was alsoexcellent.

Example .-TernaryVariation Six parts of PVA (99-100% free hydroxylgroups) was added to 94 parts of water and solution effected as inExample 1. Dialdehyde starch (90% oxidized) solution was also preparedas given in Example 1. The dialdehyde starch solution was added to thePVA solution, the quantities being selected so that forty parts of PVAto one part of dialdehyde starch was present. Colloidal silica (havingan average particle size between 0.015 and 0.02 micron, a surface areaof about 175225 square meters per gram,

an n of 1.46, and a 99.9% silicon dioxide content on a dry basis) in anamount equal to the amount of PVA, or six parts of silica, was dispensedin 94 parts of water, and the slurry added to the PVA-DAS solution.After mixing thoroughly, a ratio of 49.4 parts of PVA to 49.4 parts ofsilicon oxide to 1.2 parts of dialdehyde starch was present in thecomposition.

Application, setting, and testing were completed as in Example 4. Theresults were identical to those reported in Example 4.

Example 6.Ternary-Variation The procedure of Example 5 was repeatedexcept that silica in an amount equal to two-thirds the weight of PVAwas added to give a ratio of 40 parts of PVA to 27 parts silicon oxideto 1 part of dialdehyde starch, or 1.4 parts of dialdehyde starch to59.5 parts of PVA to 39.1 parts of silicon oxide per parts.

Application, setting, and testing was as given in Example 4. The resultswere the same as given in Example 4.

Example 7.

Additional binary compositions were made up in accord with Examples 1through 3 and additional ternary compositions were made up in accordwith Examples 4 through 6. These were coated upon base sheet materialsof suitable characteristics in accord with the preceding examples. Ineach case, the relative amounts of the ingredients in either the binaryor ternary systems were in accord with the graph of FIGURE 4 and inaccord with Table I hereof. In each case of the binary systemcomposition and the sheet material coated therewith, a satisfactoryresult was obtained. The masters produced from this binary compositioncoated sheet material were found to be suitable in the same manner asthe products of Examples 1 through 3.

When a ternary composition was used for coating of the base sheetmaterial stock, the results were in accord with those given in Examples4 through 6, in each case the resuits on the various types ofduplicating or reproduction equipment being excellent. In addition, thereproductive characteristics of the master were subject to lessvariation from run to run than observed when using masters produced fromsheet materials coated with the binary compositions.

Although the coating compositions of the invention have beenparticularly described with reference to the coating of a base sheetmaterial having certain ultraviolet transmission characteristics andwhen applied to such base sheet material produce an excel-lent coatedsheet suitable for use as a master in reproduction according to all ofthe various types of processes previously described, it is to beunderstood that the coating compositions of the invention may also beemployed or applied in the coating of an opaque sheet material or asheet material not having the particular desirable ultraviolettrans-mission characteristics previously set forth. Such coated sheetmaterials are nevertheless of value as masters in reproduction processeswhich do not require ultraviolet transmission, such as offsetlithography, heat absorption processes, electrostatic processes, and thelike.

It is to be understood that various substitutions of equivalents will beapparent to one skilled in the art, and that various modifications andalterations may be made in the process, compositions, and products ofthe present invention without departing from the spirit or scopethereof, wherefore the present invention is limited only by the scope ofthe appended claims.

I claim:

1. A duplicating master adapted for use in duplicating processes ofeither the ofifset or the differential l ght transmission-absorptiontype, comprising a base sheet material of parchmentized paper having atleast one surface thereof uniformly coated with a material comprising,per 100 parts of the stated ingredients, polyvinyl alcohol (PVA) anddialdehyde starch (DAS) in relative proportions of 50 to 97.6 parts ofPVA to 50 to 2.4 parts of DAS, the starting PVA being characterized byhaving at least about ninety-five (95) percent of its existing hydroxylgroups present as free unesten'fied hydroxyl groups, the starting DASbeing characterized by containing at least about fifty (50) percent ofstarch 2,3-dialdehyde, the said coating being substantially transparentwhen set on the surface of the base sheet material employed, the coatedsheet material having at least a five pound per inch (machine direction)wet tensile strength as tested according to TAPPI Test T 456 m49, aminimum de gree of ultraviolet transmission of at least twenty-five (25)percent as compared with air using an ultraviolet beam having a peak atabout 3650 Angstrom units, as transmitted through a Corning filter No.5860 and determined with a photoelectric transmission densometer(Photovolt No. 5012), and the total solids coated on the base sheetmaterial being in the range of 0.1 to 30 pounds per 3,000 square footream per side of base sheet material.

2. A duplicating master adapted for use in duplicating processes ofeither the otfset or the difierentiatl light transmission-absorptiontype, comprising a sheet material of claim 1 having indicia upon thecoated surface thereof in a medium reproductive in both offset anddifferential light transmission-absorption types of reproductionprocesses.

3. A duplicating master adapted for use in duplicating processes ofeither the offset or the differential light transmission-absorptiontype, comprising a base sheet material having at least one surfacethereof uniformly coated with a material comprising, per 100 parts ofthe stated ingredients, polyvinyl alcohol (PVA) and dialdehyde stach(DAS) in relative proportions of 50 to 97.6 parts of PVA to 50 to 2.4parts of DAS, the starting PVA being characterized by having .at leastabout ninety-five (95) percent of its existing hydroxyl groups presentas free unesteritied hydroxyl groups, the starting DAS beingcharacterized by containing at least about fifty (50) percent of starch2,3-dialdehyde, the said coating being substantially transparent whenset on the surface of the base sheet material employed, the coated sheetmaterial having at least a five (5) pound per inch (machine direction)wet tensile strength as tested according to TAPPI Test T 456 m-49, aminimum degree of ultraviolet transmission of at least twenty-five (25)percent as compared with air using an ultraviolet beam having a peak atabout 3650 Angstrom units, as transmitted through a Corning filter No.5860 and determined with a photoelectric transmission densometer(Photovolt No. 5012), and the total solids coated on the base sheetmaterial being in the range of 0.1 to 30 pounds per 3,000 square footream per side of base sheet material.

4. A duplicating master according to claim 3, wherein the starting PVAis at least about 99% hydrolyzed and the starting DAS contains at leastabout 75% of starch 2,3-dialdehyde.

5. A duplicating master according to claim 3, wherein the starting DAScontains at least about 90% starch 2,3-dialdehyde.

6. A duplicating master according to claim 3, wherein the weight ratioof PVA to DAS is about ten to one.

7. A duplicating master according to claim 3, wherein the base sheetmaterial is about 28 to 50 pounds per 3,000 square foot reamparchmentized paper.

8. A duplicating master according to claim 7, having a minimumultraviolet light penetration of at least about 40% as compared with airusing an ultraviolet beam having a peak at about 3650 Angstrom units astransmitted through a Corning filter No. 5860, as determined with aphotoelectric transmission densometer (Photovolt No. 5012).

9. A duplicating master adapted for use in duplicating processes ofeither the offset or the differential light transmission-absorptiontype, comprising a sheet material of claim 3 having indicia upon thecoated surface thereof in a medium reproductive in both otfset anddifferential light transmission-absorption types of reproductionprocesses.

10. A duplicating master adapted for use in duplicating processes ofeither the offset or the differential light transmission-absorptiontype, comprising a base sheet material having at least one surfacethereof uniformly coated with a material coprising, per 100* parts ofcoating composition, polyvinyl alcohol (PVA) and dialdehyde starch (DAS)in relative proportions of 0.1 to 97.6 parts of PVA to 0.1 to 72 partsof DAS, the starting PVA being characterized by having at least aboutninety-five (95) percent of its existing hydro-xyl groups present asfree unesterified hydroxyl groups, the starting DAS being characterizedby containing at least about fifty (50) percent of starch2,3-dialdehyde, said coating material additonally containing about 0.1to about 95 parts per 100 parts of coating composition of a particularmineral consisting essentially of silicon dioxide having an averageparticle size not greater than two (2) microns and refractive index (11not greater than 1.6, the said coating being substantially transparentwhen set on the surface of the base sheet material employed, the coatedsheet material having at least a five (5) pound per inch (machinedirection) wet tensile strength as tested according to TAPPI Test T 456m-49, a minimum degree of ultraviolet transmission of at leasttwenty-five (25) percent vas compared with air using an ultraviolet beamhaving a peak at about 3650 Angstrom units, as transmitted through aCorning filter No. 5860 and determined with a photoelectric transmissiondensometer (Photovolt No. 5012), and the total solids coated on the basesheet material being in the range of 0.1 to 30 pounds per 3,000 squarefoot ream per side of base sheet material.

11. A duplicating master according to claim 10 wherein the coatingcomposition comprises from about 15 to 97.5 parts of PVA, from 0.1 toabout parts of said silicon dioxide, and from 0.1 to about 55 parts ofDAS.

12. A duplicating master according to claim 10, wherein the starting PVAis at least about 99% hydrolyzed, the starting DAS contains at leastabout of starch 2,3- dialdehyde, and the silicon dioxide has an averageparticle size less than .05 micron.

References Cited by the Examiner UNITED STATES PATENTS 2,230,981 2/1941Toland et al. 101--149.2 2,280,985 4/1942 Toland et al. 10l149.2 X2,550,326 4/1951 Brown 101149.2 2,729,575 1/1956 Newman 101-1492 X3,016,823 1/ 196-2 Thurlow 101149.2 3,055,295 9/ 1962 Perkins 101-14923,058,827 10/1962 Graham 96111 DAVID KLEIN, Primary Examiner.

WILLIAM B. PENN, Examiner.

1. A DUPLICATING MASTER ADAPTED FOR USE IN DUPLICATING PROCESSES OFEITHER THE OFFSET OR THE DIFFERENTIAL LIGHT TRANSMISSIIN-ABSORPTIONTYPE, COMPRISING A BASE SHEET MATERIAL OF PARCHMENTIZED PAPAER HAVING ATLEAST ONE SURFACE THEREOF UNIFORMLY COATAED WITH A MATERIAL COMPRISING,PER 100 PARTS OF THE STATED INGREDIENTS, POLYVINYL ALCOHOL (PVA) ANDIDALDEHYDE STARCH (CAS) IN RELATIVE PROPORTIONS OF 50 TO 97.6 PARTS OFPVA TO 50 TO 2.4 PARTS OF DAS, THE STARTING PVA BEING CHARACTERIZED BYHAVING AT LEAST ABOUT NINETY-FIVE (95) PERCENT OF ITS EXISTING HYDROXYLGROUPS PRESENT AS FREE UNESTERIFIED HYDROXYL GROUPS, THE STARING DASBEING CHARACTERIZED BY CONTAINING AT LEAST ABOUT FIFTY (50) PERCENT OFSTARCH 2,3-DIALDEHYDE, THE SAID COATING BEING SUBSTANTIALLY TRANSPARENTWHEN SET ON THE SURFACE OF THE BASE SHEET MATERIAL EMPOLYED, THE COATEDSHEET MATERIAL HAVING AT LEAST A FIVE (5) POUND PER INCH (MACHINEDIRECTION) WET TENSILE STRENGTH AS TESTED ACCORDING TO TAPPI TEST T 456M-49, A MINIMUM DEGREE OF ULTRAVIOLET TRANSMISSION OF AT LEASTTWENTY-VIE (25) PERDENT AS COMPARED WITH AIR USING AN ULTRAVIOLET BEAMHAVING A PEAK AT ABOUT 3650 ANGSTROM UNITS, AS TRANSMITTED THROUGH ACORNING FILTER NO. 5860 AND DETERMINED WITH A PHOTOELECTRIC TRANSMISSIONDENSOMETER (PHOTOVOLT NO. 5012), AND THE TOTAL SOLIDS COATAED ON THEBASE SHEET MATERIAL BEING IN THE RANGE OF 0.1 TO 30 POUNDS PER 3,000SQUARE FOOT REAM PER SIDE OF BASE SHEET MATERIAL.
 2. A DUPLICATINGMASTER ADAPTED FOR USE IN DUPLILCATING PROCESSES OF EITHER THE OFFSET ORTHE DIFFERENTIAL LIGHT TRANSMISSION-ABSORPTION TYPE, COMPRISING A SHEETMATERIAL OF CLAIM 1 HAVING INDICIA UPON THE COATED SURFACE THERE-
 10. ADUPLICATING MASTER ADAPTED FOR USE INDUPLICATING PROCESSES OF EITHER THEOFFSET OR THE DIFFERENTIAL LIGHT TRANSMISSION-ABSORPTION TYPE,COMPRISING A BASE SHEET MATERIAL HAVING AT LEAST ONE SURFACE THEREOFUNIFORMLY COATED WITH A MATERIAL COPRISING, PER 100 PARTS OF COATINGCOMPOSITION, POLYVINYL ALCOHOL (PVA) AND DIALDEHYDE STARCH (DAS) INRELATIVE PROPORTIONS OF 0.1 TO 97.6 PARTS OF PVA TO 0.1 TO 72 PARTS OFDAS, THE STARTING PVA BEING CHARACTERIZED BY HAVING AT LEAST ABOUTNINETY-FIVE (95) PERENT OF ITS EXISITING HYDROXYL GROUPS PRESENT AS FREEUNESTERIFIED HYDROXYL GROUPS, THE STARTING DAS BEING CHARACTERIZED BYCONTAINING AT LEAST ABOUT FIFTY (50) PERCENT OF STARCH 2,3-DIALDEHYDE,SAID COATING MATERIAL ADDITIONALLY CONTAINING ABOUT 0.1 TO ABOUT 95PARTS PER 100 PARTS OF COATING COMPOSITION OF A PARTICULAR MINERALCONSISTING ESSENTIALLY OF SILICON DIOXIDE HAVING AN AVERAGE PARTICLESIZE NOT GREATER THAN TWO (2) MICRONS AND REFRACTIVE INDEX (NC20C$) NOTGREATER THAN 1.6, THE SAID COATING BEING SUBSTANTIALLY TRANSPARENT WHENSET ON THE SURFACE OF THE BASE SHEET MATERIAL EMPOLYED, THE COATED SHEETMATERIAL HAVING AT LEAST A FIVE (5) POUND PER INCH (MACHINE DIRECTION)WET TENSILE STRENGTH AS TESTED ACCORDING TO TAPPI TEST T 456 M-19, AMINIMUM DEGREE OF ULTRAVIOLET TRANSMISSION OF AT LEAST TWENTY-FIVE (25)PERCENT AS COMPARED WITH AIR USING AN ULTRAVIOLET BEAM HAVING A PEAK ATABOUT 3650 ANGSTROM UNITS, AS TRANSMITTED THROUGH A CORNING FILTER NO.5860 AND DETERMINED WITH A PHOTOELECTRIC TRANSMISSION DENSOMETER(PHOTOVOLE NO. 5012), AND THE TOTAL SOLIDS COATED ON THE BASE SHEETMATERIAL BEING IN THE RANGE OF 0.1 TO 30 POUNDS PER 3,000 SQUARE FOOTREAM PER SIDE OF BASE SHEET MATERIAL.